Booting into Safe mode is slower (but should not be 10-15 minutes).
But the fact that it booed into Safe mode may indicate you have some 3rd party products installed that are not playing nice. Or it could be that Safe mode clears some caches, and uses some more conservative device drivers, such as for the graphics.
If you can not boot normally, then it might have been caches.
If you cannot boot normally, it might be 3rd party software.
You might want to post the output from EtreCheck in a reply
<http://etrecheck.com>
copy and paste this link into your browser's URL address bar (clicking on it may not work, due to a bug in the forum software today).